In imaging devices including digital cameras, single-plate CCDs are generally used. Color filters are placed over the entire CCDs, and color images are obtained by interpolating the colors. Spectral sensitivity characteristics of the color filters are different among colors, and human-beings have characteristics to prefer vivid colors in their memory to actual colors with respect to green of trees or blue of the sky, so that color correction is performed to obtain desired colors (memorized colors).
Generally, as a color correction method, the colors based on RGB signals or YCbCr signals of image data are divided into areas, and then the signals are amplified according to gains predetermined for each area in advance, or are computed according to color correction matrices, to perform color correction. In a specific example of such a color correction method, as described in Patent document 1, in the color difference signal plane, firstly, the hues are divided into a plurality of areas by area boundary lines passing through the origin, and the position vector of an input color difference signal is divided into two vector components along neighboring area boundary lines. In addition, the vectors along the area boundary lines are linearly transformed by a transformation matrix, to perform color conversion, whereby the color correction is performed only for hues within an arbitrary area among the entire hue area.    [Patent document 1] Japanese Patent Laid-Open No. 176656/2002, “COLOR CORRECTION CIRCUIT”    [Patent document 2] Japanese Patent Laid-Open No. 115588/2000, “IMAGING DEVICE, IMAGING DEVICE CONTROL METHOD, AND STORAGE MEDIUM THEREFOR”